Grabbed_Crow_Mobe

Assume you had an 05 Z51 LS2 and were going to do the following mods:
Halltech MF103
Kooks 1 7/8”
Mild Cam
NW 102 TB
Tune
Pfadt sways

For the money, would you rather add:
Pfadt single adjustable coilovers

OR:

Fast Intake
Cat delete
CNC’d 243 heads
DRM valved Bilsteins

I’m assuming that the second option would yield an additional 40 HP or so.

I realize that you could do some additional power mods with the coilovers (ported intake, cat delete, etc). What I’m trying to figure out is how significant the coilover addition is to a track car vs stock springs, aftermarket shocks and HP. Are they worth giving up additional HP?

Interested in your opinion/experience!

Bill Dearborn

Any thing that gets you around a corner faster and allows you do get on the throttle sooner as you come out of a turn is far better than HP. It takes a lot more HP to make up for the couple of mph faster you will go through the corner and the jump you get by being able to get on the throttle 20 ft sooner than the other guy. It's like being at a drag strip and your competitor is allowed to make a rolling start at 2 mph and go wide open at the start line while you can't launch until his rear bumper has passed your front bumper. How much HP does it take to make up that difference?? Then you have to think about the other end of the straight where your improved cornering speed adds a braking advantage reduces the amount of braking you need to do. Once safety and reliability items are addressed the mods should be prioritized this way: Brakes (so you can brake later more times), suspension, reduced weight (free HP) and finally added HP.

Bill

brkntrxn

Well stated!

Werks

Agree with what Bill said. I would also add that suspension is probably one of the most critical items on the car and not an area that you should cut corners on. If you are planning on tracking the car and you are going to spend the money to buy coil-overs then get ones with separate compression and rebound settings aka 2-way adjustable.

I'm editing this because I should probably clarify what I was saying.Your best bet is going to be to either go with non adjustable coilovers or if you are going to go with adjustable coilovers like you mentioned in your original post go with 2 ways not single adjustable.

2 GTOs

I suggest this order:

1) Connect the driver with the car (add safety equiptment)
2) Connect car with road (tires, brakes, suspension)
3) Add performance (power, data logger, etc)

No point in having the power if you can't safely get it to the ground.

Gman57

Check with Randy @ DRM about their coilovers and have $$$ left over to do other mods.
I have them and very happy with them
G

AU N EGL

1) contact patches: Seats, harness, brake pads, brake cooling and tires.
2) Cooling: larger radiator, oil cooler and trans cooler.
3) nothing but seat time.

Good Luck

jbondfl

I look at it this way...
That Spec-Miata isn't passing me because I lack HP.
If/when I find that the only cars passing me have more HP than I do, that's when I'll start looking at power adders.
Until then, I'll concentrate on learning to drive better and improving the cars ability to take advantage of my skill improvements.

redtopz

So you haven't done the first set of mods yet? Skip the cam and TB and just do headers and tune. Then spend your money on anything but more power. How often do you plan to go to the track? What kind of tires will you run? Go with safety, cooling, and brakes first, possibly dry sump if you are going to track regularly. Then suspension (I like LG coilovers ) and bushings. In a corvette, more power would be the LAST thing I would add. Seat time is the best way to spend your money. Then when the C6Z's and ZR1's see you turning faster laps you can say "it's just a stock LS2".

Jason

If I had an LS2 I'd be spending my money on oiling. And a spare motor.

Grabbed_Crow_Mobe

Great feedback!

Looking at the comments, I should have put this question in context and given a short history of where I am with the car. Brief history:

1. Seat time -> Started completely stock and concentrated on seat time and taking classes.
2. Brakes -> Started getting brake fade (which scared the **** out of me a few times) so I improved the braking system: fluid/pads/rotors/cooling/SS lines
3. Tires -> Instructor recommended that I go to R-comp tires as I was having problems keeping the run-craps planted. Got a set of dedicated track wheels and tires: CCW and Toyo R888s.
4. Cooling -> Shortly thereafter I started getting higher oil/coolant temps so I added bigger radiator and external oil cooler.
5. Safety -> Somewhere during this process I installed a harness bar and harness. Haven’t found a seat that I like yet so I’ve been running OEM belts.

I do about 10 events a year and see that frequency continuing. I drive my car to the track so going to a stickier tire like Hoosiers isn’t a realistic option (and may be a great argument against more HP).

The suspension is next and I fully appreciate the notion that adding HP is the last thing that should be done. The basis of my question was to determine how important it is to spend money on a set of coilovers vs aftermarket shocks and other upgrades.

I was trying to look ahead to what HP improvements I would make when I eventually got there and compare the pricing of various options with coilovers. Ultimately, I’m trying to decide if coilovers are worth the investment. Sounds like a resounding yes?

kmagvette

What Bill said...and GMan57 too.

The DRM Coilovers are fantastic. Sure there are more expensive shocks with additional degrees of adjustablity, but for the price the DRM's are awesome. I run them paired up with the Pfadt Comp Bars on very sticky rubber (Pirelli Rolex rubber) and have no issues.

A good seat is hugely important for safety and driver performance.

CHJ In Virginia

I agree with the previous posters. With your stated mods, it is indeed suspension time. Definitely go with the coilovers, heavier sway bars and a proper alignment. You will knock seconds off your lap times. I like my LG GT-2 adjustable coil overs and Hotchkiss sway bar combination.
It is also time to get serious on the safety situation !!! You are fast enough that the stock belt ain't gonna cut it any longer. Get a proper seat, 6-point harness AND A HANS device.
Once you have a season under your belt with the suspension mods, and you are getting all the car will give, then it is time to start looking for power mods.

dvandentop

3rd on the drm coil overs good products and bang for the buck and dont need a race engineer to worry about adjusting all their settings

Grabbed_Crow_Mobe

Does anyone use DRM coil overs on the street? I noticed that they aren't adjustable and was curious if they were tolerable for street driving.

rmackintosh

Pretty much what has been said here....if on track:

1. Safety FIRST
2. Suspension and Brakes
3. Performance adding

95jersey

Lots of great advice here and I think your getting similiar feedback from everyone

my $0.02 in this exact order

1) Safety and reliability mods to ensure you and the car are protection
2) 2 years of seat time on stock car and tires from starting as a Novice
3) Brakes and Tires (the 2 go hand in hand in my opinion)
4) 1 more year of seat time until you get to upper intermediate
5) suspension
6) finally REAL power

Let me just say, I don't see an intake, tune or exhaust as real power mods...I would do these on a street car regardless, but I unless you are an advanced student, you will not really benefit from the cam. I pass all kinds of cam'd cars in my stock motor Z. The cam will teach you bad habbits and give you a false sense of speed, since you can simply catch people on the strait. The cam will just hide your mistakes.

TorontoC6

Your upgrade sequence shows good judgement. I have a similar car (2006 Z51) and have been tracking it for 3+ years.

If you had'nt already bought them, I might have suggested waiting on the R-comps. I am not saying that the R888's are bad, but there are tires more capable than the Goodyears that will last longer (15+ track days) than the R888 and are more useful as street tires (e.g. Bridgestone RE-11's, Hankook RS-3, Kumho XS, Michelin Super Sport). You give up a little grip but I believe that you can learn more quickly on those tires than going to R-comp as they break away more gently and communicate more before they break. They are also better in the rain than the R888. Once you start running R-comps, you get spoiled.

With respect to suspension, I encourage you to get coilovers but I would also suggest installing a bushing kit (e.g. pfadt) as the stock rubber bushings deflect significantly and you loose all your camber when the suspension is loaded in the corner. I did these before I did coilovers (LG G2) and bars and even with the stock Z51 suspension, it was very noticeable.

I also upgraded seats as groups like NASA won't let you run harness with stock seat. I went with Sparco R100 which are cheap, have decent bolsters and have adjustable backrest (good for comfort and support, bad for increased risk of failure in accident versus fixed back seats). If you are going to run harness, also get a HANS.

As HP upgrades, the only thing that I did was breathing related - vararam, fast 102 intake, headers, and tune. Once you crack the motor, reliability can become more of an issue. As others have pointed out, oil starvation is only a matter of time with upgraded suspension, tires, and driver ability.

Half the fun is figuring out the next set of mods and then seeing what effect they have. It's more fun making changes at a gradual pace with lots of track days to test out the changes.

Grabbed_Crow_Mobe

>>If you had'nt already bought them, I might have suggested waiting on the R-comps.

Is it too late to go back? I debated this decision over and over again at the time. I originally wanted to buy a dedicated set of track wheels/tires and after doing extensive research on tire sizing vs wheel sizing, I learned that there weren't many options. Either buy another set of stock wheels and go RE-11’s (or similar) with stock tire sizing or buy a used set of T1 CCWs and go with r-comps with wider tire sizing and less unsprung weight. I’m running 295 up front and 305 in the back now and they’re lighter than stock. Based on feedback from my instructor at the time, I went with the r-comps. You’re definitely right about the lack of communication on the r-comps. When they go, they go. Do RE-11s really last 15+ track days? If that’s the case, buying a used set of stock wheels makes up for the cost of the tires. I’m only getting 5 or so track days out of the R888s now and that’s after remounting them from side to side after 3 days due to tapering.

>> but I would also suggest installing a bushing kit (e.g. pfadt)

Funny you should mention that. I have a set of pfadt poly bushings sitting in my garage waiting to be installed. I currently have the neg camber maxed out at all four corners and am hoping that the decreased deflection combined with the added ~-0.8* up front will give me better grip/tire wear.

Hypothetical question: Would you rather have my current setup: Toyo R888 295 front/305 rear with stock Z51 suspension <OR> RE-11s on stock wheels with coil overs and stiffer sway bars?

>> As HP upgrades, the only thing that I did was breathing related - vararam, fast 102 intake, headers, and tune.

After more research and feedback from this thread, I’m considering something similar and forgoing the cam. Since I have the ’05, I’m also considering a later model differential.

>> As others have pointed out, oil starvation is only a matter of time with upgraded suspension, tires, and driver ability.

I've looked into this as well. Considering an accusump but still researching.

Thanks everyone for the feedback. I’m constantly amazed on how great this community is!

PushinTheLimit

Many of us have seen plenty of the LS2, LS3 and LS7 oiling issues the past few years. An accusump will help a little, but won't cure the problem. A good dry sump is typically the answer here... but even then, we've seen a few blow up.

The only HP mods I would ever do to a corvette track car would be intake, tune and exhaust. You could add headers into that since it's beneficial.

A good set of coilovers like some have suggested is a good start. I have Pfadt single-adj. on mine and it feels better than what I had before (T1 springs with Koni single-adj. shocks). Better bushings like Pfadt's are good as well. Lots of cooling mods (oil coolers, diff cooler and trans cooler on my car) really help.

You won't believe how much better it'll feel once you track with a good seat... you will probably pick up some time on that alone since you're not fighting to stay in your seat!

As for tires, since you already seem to have a few days under your belt... going to a sticky tire isn't out of the question. For me personally, I started using Hoosier A6's and R6's on my 2nd ever track day. But I had been autoxing for 2 years before that so I felt comfortable making that transition when I did. I also did that so I would know how the car would handle in race situations since I knew I would eventually go into W2W competition.

If you decide you want some T1 CCW Classics, let me know and I can set you up.